In the modern political view of India, the very word Caste is looked at as controversial. The word Caste was brought in India by the Portuguese with their term  Casta ”,meaning race.
The term “caste system” is of British colonial creation and was first used in 1871 census in India.
Varna   and  Jathi :
From time immemorial we have been having the societal division concept through  Varna and  Jathi. This concept of  Varna and  Jathi were combined and transformed into caste system by the colonial British administrators for their administrative nomenclature and classification.
Varna :
The word  Varna is etymologically from  Vr meaning  “to choose”.

There are four  Varna in India. They being:

As the word  Varna suggests it is to choose ones way of life among these 4 primary streams.

The word  Varna also indicates colour. Because you chose the colour you want to use.
Jathi :
Under or inside the  Varna is the concept of  Jathi.

Jathi stands for trade guilds, stock, variety. It also refers to species or nation. These two concepts of division of labour in society based on choice attitude and aptitude of the individuals practiced from ancient and medieval India was summarily clubbed as caste by British colonial administrators.

Caste emanate from Vishnu. This statement has been much maligned in the last 100 years without understanding what it really means. In this subject capsule we look at how these four  Varna evolve from the body of Vishnu. Vishnu here is looked at as being vertical in posture and hence the caste system is looked at hierarchal. The same Vishnu is also often shown in a reclining posture, in which case the same  Varna system can be looked at horizontally instead of vertical. This change in alignment and the thought that goes with it changes the whole perspective of how the  Varnasystem evolved and was an integral part of the organization and progress of Indian society.

The caste system of India was not tightly bound but had the concept of migration from one caste to another in built based on the occasion of the individual person. Most of the great Rishi, the Vedic scholars and the other great scholars of the Indian civilization were born in the  Sudra varna and because of their abilities and realization migrated to become Brahmana.

Kings of Bharath:
Most of the kings of India also belong to the Sudra Varnaand because of their kingship became Kshatriya. This migration was a recognized aspect of the Indian  Varna system.

This we can see all through the 5000 years of Indian History.

Caste Stratification:
It is in the medieval period during the onslaught and later in the colonial period the caste stratification took place which led to the debacle and down slide of India.

Caste - a pan religious reality:
The horrors of caste are not limited to the Hindus alone. The Indian Christians also follow the practice of caste system very rigidly. They have segregated churches, segregated cemeteries, segregated services, and segregated processions.
The Muslims also have practiced the caste system in India with Azraf being the noble and the Arzal being the degraded. The  Mayazur are the low caste bonded labour in Pakistan.
Even among the Sikhs the caste does exist in reality as the  Jat Sikh and the  Chamar Sikh.
From this it is clear that the concept of caste is not just in the Hindu religion but it is a pan religious reality of India.

Social leaders:
Various social leaders of India whose names are noble and endless have worked tirelessly to abolish or mitigate the horrors and stratification of caste whenever it has reared its ugly head in the society.

Colonial wreck:
The colonial rule in India wreaked the economy of the land. Probably the most affected by the colonial rule were the  Sudra whose property, education, vocation and stature were snatched away from them by the British administrators.

Changes adapt:
Today, as India is progressing we see a cycle of changes happening. With these changes, the  Jathi Varna concept of India needs to adapt itself. This concept held the fabric of the Indian society in its progress for many thousand years.

The realization that should come in us now, is that the 3 upper castes namely BrahminKshatriyaand Vaisyashould realize that they all belong to the common stock of people and due to opportunities and historical reasons they are better off socially now. The above 3 castes are of the same genetic stock as the  Sudra. They belong to the same land, same society, and have all been one through the ages. This realization should enthuse these three castes to take a concrete effort by themselves in uplifting the  Sudra brethren through positive effort.